Dark-blue sulfur dye.



UNITED STATES Patented November 22, 1904.

PATENT OFFICE.

AUGUST LEOPOLD LASKA, OF OFFENBACH-ON-THE-MAIN, GERMANY,

ASSIGNOR TO THE FIRM OF K. OEHLER, OF OFFENBACH-ON-THE- MAIN, GERMANY.

DARK-BLUE SULFUR DYE.

SPECIFICATION forming part of Letters Patent No. 775,570, dated November 22, 1904.

Application filed May 26, 1904. Serial No. 209,841. (No specimens.)

To all w/wm it may concern:

Be it known that LAUsUs'r LEOPOLD LASKA, doctor of philosophy, chemist, residing at 5 Gerberstrasse, Offenbach-on-the-Main, Germany, have invented new and useful Improvements in Dark-Blue Sulfur Dyes, of which the following is a specification.

From the indications made in chemical literature about those derivatives of diphenylamin which result from the condensation of dinitro-chloro benzene (OhNOzzNOz lflzi) with the derivatives of p-amidophenol,wl1erein both the ortho positions to the oXy group are substituted, it is to be supposed that by converting the said diphenylamin derivatives into sulfur dyes by melting it with alkali polysulfids an elevated temperature is necessary for instance, in the French Letters Patent No. 336,630 it is said that a dyestuff from dinitrodichloro-oxydiphenylamin of the following constitutional formula begins to form not earlier than at 160 centigrade and will only be finished at 170 centigrade. In the German Letters Patent No. 133,940 a sulfur dye is described, derived from dinitro-phenyl-oxytolylamin-carbonic acid, the formation of which is, according to the statements in the German Letters Patent No. 129,885, completed at 150 centigrade. Contrary to these facts, I have found that at a very much lower temperaturethat is to say, already at about 100 centigrade the dinitro phenyl chloro oxytolylamin of the constitution can be converted to a sulfur dye, and its shades,

also contrary to the above-mentioned dyestufis, are not black, but dark blue.

The dinitro phenyl chloro oxytolylamin may be obtained by the condensation of dinitro-chloro benzene (Ol:NO2:NO2 1:2:4) with para-amido-ortho-chloro-ortho cresol, (OH: CH3:NH2:Ol:1:2:4E:6,) whereas this body results from reducing the corresponding nitro compound by means of zinc and acetic acid. It melts at about 139 to 1&0 centigrade and is rather difficultl y soluble in water. In order to carry out the condensation, 153.5 parts of para amido ortho chloro ortho cresol and 202.5 parts of dinitro-chloro benzene are boiled together in an alcoholic aqueous solution during about four hours in a vessel provided with a reflux condenser, while adding one hundred and forty parts of sodium acetate in order to bind the nascent hydrochloric acid. The resulting dinitro-phenylchlorooXytolylamin separates as a reddish precipitate. It is filtered off and dried as usual. It dissolves in concentrated sulfuric acid and in diluted soda-lye with a brown color and precipitates from the latter solution in orange-red flocks on addition of hydrochloric acid.

The following example will illustrate the manner in which the dyestufi may be prepared: Melt together three hundred parts of crystallized sodium sulfid, one hundred and twenty parts of sulfur, and two hundred parts of water. Next, at to centigrade, add seventy-five parts of dinitro-phenyl-chlorooxytolylamin. Then heat the whole in a reflux condenser. After about twenty hours the formation of the dyestufi is finished. Then dry the melt by evaporating at to centigrade. The coloring-matter thus obtained gives in Water a greenish-blue solution from which it precipitates in brown flocks on addition of hydrochloric acid. It dissolves in concentrated sulfuric acid with a blue color and is dyed on cotton from a bath containing sodium sulfid, yielding dark-blue shades of a very good fastness.

The temperature during the melting process may be raised until centigrade without essentially interfering the shade. When increasing the temperature, it becomes some more blackish. It is also possible to isolate the dyestuif from the solution by a current of air or precipitating by an acid.

Now, what I claim, and desire to secure by Letters Patent, is the following:

1. The process of producing a dark-bluesul- 100 to 125 centigrade, the dinitro-phenylwith para amido ortho chloro ortho cresol (OH:OH3:NH2:Cl 122:4:6) which yields on cotton when dyed in a bath containing sodium sulfid, dark-blue shades, dissolves in concentrated sulfuric acid to a blue and in water containing sodium sulfid to a greenish-blue solution from which it separates on addition of hydrochloric acid, in brown flocks, all substantially as herein described and claimed.

- In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

AUGUST LEOPOLD LASKA.

Witnesses HERMANN WEIL, ELsA KAUFFMANN. 

